Tuning apparatus for radio receivers



3 Sheets-Sheet:` 1

H. D. GREGORY TUNING APPARATUS FoR RADIO RRCEIVERS Filed Aprila, 19:52

Nov. 23, 1937.

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Nov. 23, 1937. H. D. GREGORY I TUNING APPARATUS FOR RADIO RECEIVERSFiled April l, 1932 3 Sheets-Sheet 2 am# w, a wo VH n m@ A m d. H @f HTUN/N6 .DRUM

Nov. 23, 1937.

H.' D. GREGORY 2,099,733

TUNING APPARATUS FOR RADIO RECEIVERS Filed April 1, 19.52 3Sheets-Sheel'l 3 Hqfold. Gregory, by

Patented Nw. 23, 1937 TUNING APPARATUS FOR RADIO RECEIVERS Harold D.Gregory, Haddon Heights, N. J., as-

signor to Radio Corporation of America, New York, N. Y., a corporationof Delaware Application April 1, 1932, Serial No. 602,548

' 11 Claims.

My invention relates to improvements'in preselection time-controlledtuning apparatus for radio receivers.

One of the objects of my invention is to provide improved apparatus ofthe character referred to which automatically tunes the radio receiverto a pre-selected station and also adiusts the volume controllautomatically to a preselected position.

Another object is to provide improved apparatus of the characterreferred to which can be easily and quickly set for a given programwithout the necessity for adjustment of any parts such as knobs, slidersor the like.

Other objects and advantages will hereinafter appear.

In one embodiment of my invention, tuning and volume control drums aredisposed one within the other and supported for rotation independentlyof each other about a common axis. The adjacent surfaces of the drumsare each provided with contact segments separated by a narrow strip ofinsulating material extending from end to end of the drum and throughsubstantially 360 degrees. to form a spiral. The outer drum is geared tothe tuning condenser of a radio receiver, and the inner drum is gearedto a shaft for adjusting the volume. The drums are driven by separatereversible motors. In setting up the apparatus for a given selectedprogram whereby different stations will be tuned in automatically at thedesired time, control pins are inserted between the adjacent contactsurfaces ofthe drums at desired positions around the same, representingtwelve hours of the day. Each pin is provided with two contacts, oneengaging the surface of the outer drum., the other engaging the surfaceof the inner drum. 'I'hese contacts are adjustable longitudinally of thepin to determine the positions to which the control drums are moved bythe driving motors.

By means of a switch rotated by the hour shaft of a suitable clockmechanism, and which is closed by mechanical engagement with the variouspins, the operating circuits for the motors are completed at timesdetermined by the positions of the pins. Operation of the motorscontinues until the insulating strips referred to engage the contacts ona particular pin, at which time the control drums are at the desiredpositions for tuning in the new station and making the new desiredvolume adjustment. Pins are also provided for shutting oi! the radioreceiver at any/desired time, depending upon the position (Cl. Z50-20)at which these pins are inserted between the control drums.

A particular-embodiment of my invention is shown in the drawings,wherein Figure 1 is a vertical sectional view, partly diagrammatic, ofcontrol apparatus embodying my invention, the section being taken on theline I-I in Fig. 3;

Fig. 2 is a plan view, partly in section, partly broken away, and partlydiagrammatic, the section being taken on the line 2 2 in Fig. 1;

Fig. 3 is a front elevational view, looking toward the right in Fig. 1;

Fig. 4 is an enlarged sectional view, the section being taken on theline 4-4 in Fig. 1;

Fig. 5 is a sectional view.. the section being taken on the line 6-5 inFig. 4;

Fig. 6 is a plan view of Fig. 5;

Fig. 7 is an enlarged sectional view taken 0n the line 'I-T in Fig. 1;20

Fig. 8 is an enlarged sectional view, taken on the line B-B in Fig. 1;

Fig. 9 is a section taken on the line l-l in Fig. 8;

Fig. 10 is a section taken on the line I0-I0 in Fig. 1;

Figs. 11 and 12 are enlarged sectional views taken on the lines II-IIand I2-I2, respectively, in Fig. 1;

Fig. 13 is an enlarged fragmentary view taken from, Fig. 1;

Fig. 14 is a simplified schematic development, partly diagrammatic, ofthe various parts in Fig. 1, showing the electrical'control circuits;and

Fig. 15 is an enlarged section on the line IB-IB in Fig. 3.

With reference to Fig. 1, a tuning control drum I0 and a volume controldrum II of insulating material are disposed one within the other forrotation about a common axis I2. The drum I0 has a bearing at I3 on theinner drum for rotation with respect thereto. The left-hand end of thedrum I0 is supported for `free rotary movement by bearing blocks I Isecured to a supporting panel I5. The right-hand end of the inner drumII is supported by and has a bearing on a cylindrical bearing block Il.'I'he left-hand end of this drum is supported by and has a bearing on acasing I1 of suitable clock mechanism for driving a hollow hour shaft Iland a minute shaft I9 extending through the shaft I8. The clock casingI1 is supported by a bracket 20 secured to the panel I5. A reversiblemotor 2I has a driving connection, through gears 22 and 23, with thetuning drum I0, the gear 23 being fixed 2 on the latter. Similarly, areversible motor 24 has a driving connection, through gears 25 and 26,with the volume-control drum il, the gear 28 being fixed on vthe latter.

For the vpurpose of determining the respective positions to which thecontrol drums I0 and il are rotated control pins example, areinsertedthrough openings 3l in a plate 32 of insulating material fittedin and forming, in effect, a part of the panel Il. As more clearly shownin Figs. 4, 5 and 6, each pin is provided with a contact 33, carried bya spring strip 34 blfurcated at one end to receive a retaining screw 35.The pin 21 isprovided with a longitudinal groove 36 for receiving thestrip 34 and screw 35, and a communicating opening 31 through which thecontact 33 extends. The

` contact 33 may be adjusted longitudinally of the a radio receiver,

'81, and connections 68 pin 21 by loosening the screw 35. Thepermissible range of adjustment is increased by tapping the pin 21 at 38for the screw 35, whereby the contact assembly can be reversed, 'asindicated by the dash-line showing, to support the contact 33 foradjustment along the left-hand half of the opening 31. A similar contact39 is provided for engagement with the inner surface of the tuning drumI0. ',l'he drum i8 is provided with contact segments 40 and 4| separatedby a narrow spiral strip of insulating material 42. The drum Il,likewise, is' provided 'with contact segments 43 and 44 separated by anarrow spiral strip of insulating material 45.

As more clearly shown in Figs. 1l, 12 and 13, a normally closed switch48 is carried by an arm 41 fixed on the hour shaft i8, and a normallyopen switch 48 is carried. by an arm 49 also fixed on the hour shaft.The contact 58 loi the switch 46 is connected as shown to a brush 5iengaging a ring 52. Also, the contact 53 of the switch 48 is connectedas shown to a. brush 54 engaging a ring 55. The arms 41 and 49and therings 52 and 55 are insulated from the shaft i8 by a suitable insulatingsleeve 56. Also. the rings 52 and 55 are insulated from the arms 41 and48, as shown, by suitable insulating rings 51.

The arms 41 and 49 are electrically connected by a suitable connection58. The disposition of the arm 49 is such that as the same is rotated bythe hour shaft, the switch 48 engages a projection 59 with which each ofthe pins is provided, and is thereby closed.

The field windings 68 and 6i of the motor 2l are connected to thesegments 40 and 4i, respec-I tively, through the connections 62 and63,'the brushes 64 and 65, the commutator rings 66' and and 69. In likemanner, the eld windings 18 and 1i of the motor 24 are connected to thesegments 43 and 44, respectively, through connections 12 and 13, brushes14 and 15, commutator rings 18 and 11, and connections i8 and 19.

As shown in Fig. 2, a shaft 88 for manually adjusting the usual tuningcondenser gang 8i of indicated generally by the reference numeral 82, isgeared to the tuning drum i8 through a gear 83 meshing with the gear 23.Also, a volume control shaft 84 for manually adjusting a suitable volumecontrol resistance 85, or some other part for controlling the volume, isgeared to the volume control drum Il by the gear 88 meshing with thegear 26. An additional volume control is also provided in the form of avariable resistancel a., and is manually operable indeiendently ofoperating action oi the control 5.

21, 28, 29 and 38, for

From this it will be seen that the radio receiver can be manually tunedand adjusted at any time, by turning the usual knobs 81 and 88,independently of and without interfering with the automatic controlapparatus.

The reference numeral 89 designates a power supply switch or any otherswitch effective to place the receiver in condition for operation ornon-operation.

-The operation of my improved automatic control apparatus will now beexplained with reference, more particularly, to Fig. 14. When the hourhand 99 reaches the twelve oclock position,

for example, the switch- 48 will be closed by reason of its engagementwith the projection 59 on the pin 21.. The circuit of a relay winding 9|will then be closed through a resistance 92, a battery 93, a switch'94,a relay switch H0 valso closed at this time, as hereinafter explained,connection 95, switch 48 and connection 96. The contacts 91, 98, 89 and|08 will, thereupon, be closed against the biasing action of a spring|81.

The closed contacts '180 short-circuit the switch 89 and place thereceiver in operative condition. Since the contact 39 is in engagementwith the switch contact 4I, the operating circuit of the motor 2i iscompleted through the connection 63, the field winding 8i, the closedcontacts 91, the battery 93, the switch 94, the connection including theAclosed switch i l0, the closed switch 48 and the pin 21 back to contact39. The motor 2|, therefore, operates to rotate the tuning drum I9, andthe condenser 8| until the insulating strip 42 contacts with the contact39, at which time the motor circuit is opened. If the relative positionof contact 39 andthe drum I8 had been such that this contact had been inengagement with the contact 40,the field winding 60 would have beenconnected in circuit to cause rotation of the motor in the oppositedirection until, as before, the insulating strip 42 would engage thecontact 39.

The operating circuit for the motor 24 can be traced from contact 33through the connection 12, the field winding 10, the closed contacts 98,the battery 93, the connection 95 including the closed switch H9, theclosed switch 48, and the pin 21 back to the contact 33. The motor 24will, therefore, operate to drive the volume control drum Il and thevolume control resistance 85 until the contact 33 engages with theinsulating strip 45, at which ltime the motor circuit is opened. If thecontact 33 had been in engagement with the switch segment 44', the fieldwinding 1| would have been connected in circuit, in which case the motorwould hai/e operated in the reverse direction. The receiver will now betuned to the new station and the volume control 85 adjusted as desiredfor this station.

From the foregoing it will be s een that when the switch 48 is closed byengagement with the projection 59 of any control pin, the receiver'isset into operation by closure oi the switch 89, if it has not previouslybeen operating, and the tuning condenser and the volume control 85 areautomatically set for the particular station and volume adjustmentcalled for by the pin, as determined by the positions of the contacts 33and 39.

The closed contacts 99 operate to maintain the circuit of the relay 9|through the connection |02, the switch 94, the battery 93, theresistance 92, the winding 9|, the connection 96, the closed switch 45,and a connection |03. When, thorefore, the switch 48 moves out ofengagement with and to excite the relay winding the projection 58, therelay 'winding 8| remains excited.

If it is desired to shut off the receiver at a pre- 'determined time, aplug or stop pin |01 is used.

This plug has a projection |88 which engages the switch 48 to open theholding circuit for the relay winding 9| when the hour hand 88 reachesthe position corresponding to that of the plug |81. The spring IM isthen effective to open the various switch contacts and hold the sameopen until the switch 48 engages another control pin, such, for example,as the pin 28 in Fig. 3.

From the foregoing it will be seen that each pin calls for the tuning inof a particular station. and a predetermined volume adjustment, asdetermined by the respective longitudinal positions oi the contacts 83and 88. Itvwill also be noted that in using any control pin, the same isinserted through the desired opening 8| and pushed home, with its head|880 engaging the face of the plate 82.' For the purpose of holding thecontrol pins in such position, each of the same may be provided with aspring retaining element |08. as shown in Figs. 8 and ||l1a Iof theopening 8| with a strong snap action.

As shown' more clearly in Fig. 7, each of the openings 3| may beprovided with recesses I 88 for permitting the protruding ends of thecontacts 88 and I8 to pass through freely when the pin is insertedthrough the opening.

In the set-up as shown in Fig. 3, the receiving system will be adjustedautomatically for the following program:

At twelve oclock the receiver starting switch 89 is short-circuited andthe station WJZ is tuned in by the control pin 21. The receiver is shutofi' at one oclock by the stop pin |01. 'I'he station WOR is tuned in atthree oclock by the pin 28. 'I'he station WLIT is tuned in at oclock bythe pin 29. 'Ihe station WJZ is tuned in at seven oclock by the pin 80.is shut of! at nine-thirty oclock pin |09.

To provide for precision oi' operation, in the way of the motor circuitbeing completed 4exactly on each hour and half hour at which any controlpin might be, it is proposed to insert the normally open relay switch I0in series with the switch 48, I I I exactly on each hour and half hourby any suitable electrical contact mechanism which may be driven in anywell known manner by the clock mechanism. The adjustments are such thatwhen the switch 48 engages any pin it is closed before the relay windingI I is excited, and the exciting circuit for this winding is maintainedfor a period sumcient to allow for tuning and adjustment to the newstation, after which the winding is de-energized while the switch 48 isstill closed.

From the foregoing it' will beseen that in my improved control apparatusthe various stations are automatically tuned in and the volume controlis simultaneously and automatically adjusted to the desired point forthe respective stations,

five-thirty by the stop and that in setting up the apparatus for anyparticular program 'it is only necessary to insert the control pinsthrough the openings 8| at the desired points, these pins being pushedall the way home. With this arrangement, it is not necessary, as in manyof the various control devices proposed heretofore, for the operator toadjust any knobs or other control elements or to insert only certainportions of the control pins in selecting the particular stationdesired. Furthermore, by adjusting the volume-control resistance 88a.the

' volume-control contacts 9, which engages the edge V The receivervolume level can be varied to compensate for pronounced changes inoperating conditions. such as might be attributed to seasonalatmospheric changes. For example, ii it develops that thc 88 of thevarious control pins no longer call for the desired degrees of volumedue to some pronounced change in the general operating conditions, it isonly necessary to vary the auxiliary volume control 88a until the levelfor this and all other stations is at the desired point. After this onereadjustment, no further attention to the control 88a is required untilanother change in the general operating conditions necessitates anotherreadjustment.

It will be seen, further, that the receiver can be manually adjusted atany time, without interfering in any way with the automatic controlapparatus, for which purpose the switch 84 is openedto render the latterineffective.

The clock mechanism may be of the well known spring driven type, or maycomprise a synchronous driving motor.

Although the disclosed embodiment of my invention provides only forautomatic adjustment every half -hour, it will be apparent to thoseskilled in the art that by increasing the size of the drums and thevarious other parts proportionally, automatic tuning can be effectedevery quarter hour or less. Also, for this purpose, the control pins 21may be made flat. and generally rectangular in cross-section, with thecontacts 88 and 39 protruding from the opposite narrow edges. With suchmodifications, my improved apparatus might be made capable ofautomatically tuning and adjusting the receiver for programs preselectedover the period of an entire week, in which case the arms 41 and 48would be made to rotate at the rate of one revolution a week.

Various other modifications, such as in the shape and arrangement oi'the parts, may be made without departing from the spirit of theinvention or the scope of the claims.

I claim as my invention:

1. In a system of the character described, a. radio system havingindependently operable plural means for controlling the same, means foreffecting control operation of each of the control means, and means forgoverning said secondnamed means; said governing means including a pairof contact drums supported for rotary movement independently of eachother about a common axis, each of said drums provided with elec tricalcontacts. and a member having contacts disposed for engagement with therespective contact surfaces of said drums.

2. In a system of the character described, a radio system havingindependently operable plural means for controlling the same, means foreffecting control operation of each of the control means, and means forgoverning said secondnamed means; said governing means including a pairof contact drums supported for rotary movement independently of eachother about a common axis and disposed one within and in spaced relationwith respect to each other, the outer surface of the inner drum and theinner surface of the outer drum provided with electrical contacts.' andcontrol elements insertable between said drums and provided withcontacts engageable respectively with said surfaces.

3. In control apparatus forl a radio receiver having rotary tuningmechanism and adjustable volume control mechanism, a separate actuatingmember for each of said mechanisms, means for separately actuating eachof said members, and a plurality of manually and independentlyadjustable pins, each simultaneously cooperating with both said members.to determine the respective ranges of movement of said members by saidactuating means.

4. In control apparatus for a radio receiver having rotary tuningmechanism and adjustable volume control mechanism, an actuating memberin the form of a drum for Yeach of said mechanisms, means for separatelyactuating said drums, and a plurality of manually adjustable plugs, eachsimultaneously cooperating with both said drums to determine therespective ranges of movement of said drums by said actuating means,said plugs forming with said drums part of an operating .electricalcircuit for said actuating means.

erable dependently upon said positions and contact adjustments todetermine the controlling action with respect to the motor circuit.

6. In control apparatus for a radio receiving system, adjustable meansfor tuning said system,

means for adjusting said tuning means comprising movable drum structure,an electric motor for driving said drum structure, a plurality ofcontrol pins associated with said drum structure for controllingmovement thereof, means for supporting said pins at different radialpositions with respect to said drum structure, an operating circuit forsaid motor, switch means forming part of said circuit, a radial armcarrying said switch means into successiveengagement with said pins, andclock mechanism for driving said radial arm.

7. In control apparatus of the character described, two drums supportedone within the other in concentric and spaced relation for independentrotation about a common axis, the adjacent faces of said drums providedeach with two switch segments insulated from each other and spaced alonga spiral at their adjacent edges, means for driving said drums,electrical control circuits for said driving means, and individualcontrol elements insertable into said apparatus between said drums atselected positions around the same and each provided with two contactscngageable respectively with the pairs of switch segments, said controlelements and said switch segments forming part of said control circuits.

8. In control apparatus of the character described, two drums supportedone Within the other in concentric and spaced relation for independentrotation about a common axis, the adjacent faces of said drums providedeach with two switch segments insulated from each other and spaced alonga spiral at their adjacent edges, means for driving said drums,electrical control circuits for said driving means, individual controlelements insertable into said apparatus between said drums at selectedpositions around the same and each provided with two contacts engageablerespectively with the pairs of switch segments, said'control elementsand said switch segments forming part of said control circuits, andmeans including clock mechanism for initiating control action of saidapparatus at spaced time periods as determined by the respectivepositions of the control elements.

9. In a radio receiver having independently operable tuning and volumecontrol means, means for effecting control operation of each of the saidcontrol means, and means for governing said second named means, saidgoverning means including a pair of contact drums supported for rotarymovement independently of each other, each of said drums being providedwith electrical contacts, and a plurality of independently adjust.

able selector keys having contacts disposed for engagement with therespective contact surfaces n of said drums.

l0. In a radio receiver having independently operable tuning and volumecontrol means, means for edecting control operation of each of the saidcontrol means, and means for governing said second'named means,saidgoverning means including a pair oi* contact drums supported forrotary movement independently of each other, each of said drums beingprovided with electrical contacts, a plurality of independentlyadjustable selector keys having contacts disposed for engagement withthe respective contact surfaces of said drums, and clock actuatedmechanism for operating said drums.

11. Automatic time control mechanism-tor a radio receiver including acontrol member of said receiver, a tubular member operatively connectedwith said control member, means to rotate said tubular member to adjustsaid control member, means deiining a plurality of openings circularlyarranged about and extending longitudinally of said tubular member, aremovable plug adapted to be inserted in one oi said openings,adjustable means carried by said plug coasting with the tubular memberfor determining the direction and amount of rotation of said tubularmember, a clock mechanism, and means, driven by said clock mechanism,cooperating with said plug for determining the instant when said tubularmember begins to rotate.

HAROLD D. GREGORY.

